A label-free colorimetric strategy for facile and low-cost sensing of ascorbic acid using MnO2 nanosheets

Ascorbic acid (AA), as a key coenzyme in human metabolic pathways, plays an important role in various physiological reactions. An abnormal level of AA is found to be associated with several diseases. In this paper, we developed a label-free colorimetric method for the determination of AA by using manganese dioxide (MnO2) nanosheets. Once AA was introduced, MnO2 was reduced to Mn2+, which resulted in a remarkable color fading of MnO2 nanosheet solution. Thus, AA can be quantified by photometry in a linear range from 0.1 to 20 mu M with a detection limit of 98 nM. The detection strategy possesses the advantages of versatility and low cost and shows great potential for AA detection in clinical medicine and food safety.